There is a wide spectrum of industrial applications of cellulases. In the textile industry, cellulases are used in denim finishing to create a fashionable stone washed appearance on denim cloths using a biostoning process. Cellulases are also used, for instance, to clean fuzz and prevent formation of pills on the surface of cotton garments using a biopolishing process.
A general problem associated with enzymatic stone washing is the backstaining caused by redeposition of removed Indigo dye during or after abrasion. The “backstaining” or “redeposition” of Indigo dye reduces the desired contrast between the white and indigo dyed yarns and it can be most easily distinguished on the reverse side of denim and the interior pockets (as increased blueness). On the face side of the denim this may be seen as reduced contrast between dyed areas and areas from which dye has been removed during biostoning. In order to remove the redeposited dye, the denim manufacturers use large amounts of surfactants to make the redeposited parts white again for example to increase the contrast between abraded parts and non abraded parts of the denim in a soaping process. The heavy wash condition causes colour change or colour-fading problems for finished denim products. Also additional water has to be used in the subsequent soaping process. The problem of redeposition or backstaining of dye during stonewashing has also been addressed by adding anti-redeposition chemicals, such as surfactants or other agents into the cellulase wash.
WO 97/09410 describes that the addition of a certain type of cellulase to another cellulase having abrading activity reduces backstaining. The additional cellulase belongs to glycosyl hydrolase family 5 or 7, but it has no significant abrading effect by itself. WO 01/92453 discloses backstaining reduction by treating textile with a cutinase.
It is rare for a single endoglucanase to both provide high abrasion of denim and control indigo backstain to an acceptable level. WO 91/17243 and WO 95/09225 describe a process using a single-component endoglucanase denoted EGV with a molecular weight of 43 kD derived from Humicola insolens strain DSM 1800. WO 94/21801 describes the use in “stone washing” of a single-component endoglucanase called EGIII derived from Trichoderma longibrachiatum. WO 95/16782 suggests the use of other single-component endoglucanases derived from Trichoderma in “stone washing”. WO 2009/103237 discloses the use of an endoglucanase derived from Aspergillus fumigates in “stone washing”.
There are continued needs in the art for new endoglucanases and methods for obtaining a cellulosic textile fabric with good abrasion effect but low backstaining level, especially at low temperature.
Biopolishing is a specific treatment of the yarn surface which improves fabric quality with respect to handle and appearance. The most important effects of biopolishing can be characterized by less fuzz and pilling, increased gloss/luster, improved fabric handle, increased durable softness and/or improved water absorbency. Biopolishing usually takes place in the wet processing of the manufacture of knitted and woven fabrics. Wet processing comprises such steps as e.g. desizing, scouring, bleaching, washing, dying/printing and finishing.
There are still needs in the art for new endoglucanases and methods for obtaining a cellulosic textile fabric with strongly reduced tendency to pilling formation but without substantial weight loss of the fabric in the biopolishing process, especially at low temperature. During textile processing like desizing, scouring and soaping, surfactant especially anionic surfactant is widely used. So, there will be some amount of surfactant remaining in the fabric during biopolishing process. It is very important that the endoglucanases have good compatibility with surfactant while reaching the same level of biopolishing effect.
The present invention aims to meet these needs.